ABSTRACT More than one million people have been displaced to Lebanon by the civil war in Syria. The vast majority lives amongst the five million Lebanese and interact with them daily. At the same time, HIV prevalence has increased among Lebanese men who have sex with other men (MSM) from <2% in 2010 to >10% in 2014- 15. In our recent study of 290 MSM in the Beirut area, 25% were born in Syria. They experienced more discrimination and abuse, were more likely to exchange sex for drugs, money, or goods, and less likely to have ever been tested for HIV than their Lebanese-born counterparts. We are proposing an exploratory study to obtain a larger sample of 1,000 MSM consisting approximately of 60% Syrian-born and 40% Lebanese-born MSM to (1) confirm the increased HIV prevalence in the MSM population, (2) quantify differences in HIV testing rates and HIV incidence, and (3) determine differences in access to and retention in HIV treatment for those testing HIV positive. Using the Minority Stress Model, we aim to explore if forced migration, minority stress, stigma associated with both sexual minority and refugee status, mental health difficulties, the lack of economic opportunity, and sexual and substance use behaviors among Syrian MSM living in Lebanon, in comparison to their Lebanese-born counterparts, are associated with lower rates of HIV testing among Syrian-born MSM, increased sexual risk taking, and diminished access to HIV care. These will be ascertained from the data collected from the thousand MSM and augmented by qualitative data collected from a subsample of 72 men, 24 who are HIV-positive and 24 low risk and 24 high-risk HIV- negative men of both Syrian and Lebanese nationality. Qualitative data collection and analysis will focus on personal life histories of significant events, social and sexual relationships, migratory experiences, socio- economic and substance use influences on sexual behavior, and access to and use of HIV prevention and treatment services. A mixed methods approach will combine the quantitative and qualitative data obtained through this exploratory study with the intention of developing one or more interventions to reduce HIV incidence and increase access to and retention in HIV care in a country in which HIV prevalence in the MSM population has been rapidly increasing. The opportunity here is to identify, respond to, and prevent an incipient HIV epidemic occurring within a context of massive population displacement and migration.